Given: Angle L N O ≅ Angle L N M Angle O L N ≅ Angle M L N Prove: Angle L N O ≅ Angle L N M Triangles L O N and L M N share common side L N. Angles O L N and N L M are congruent. Angles O N L and L N M are congruent. It is given that angle LNO is congruent to angle and angle OLN is congruent to angle . We know that side LN is congruent to side LN because of the . Therefore, because of , we can state that triangle LNO is congruent to triangle LNM.